Cardiovascular diseases, respiratory diseases, and gastrointestinal diseases have been distinguished according to sounds auscultated from the body of a patient. Based upon measurements taken of the different sounds, medical practitioners have been able to diagnose diseases and proceed with treatments.
In order to make a precise diagnosis of an ailment based upon auscultated sounds, extensive empirical knowledge of various and diverse forms of auscultated sounds is necessary. Until recently, auscultation was more art than science since making a diagnosis was based mainly upon the trained ear of a caregiver and not based upon measured data from recorded sounds.
With the advent of digital/electronic stethoscopes, auscultated sounds can be recorded in digital form, and software programs can then manipulate the data in order to analyze characteristics of the data. From this analysis, more precise diagnoses can be made based upon objective criteria and not just upon the trained ear of the attending caregiver.
It is well known to measure auscultated sounds from humans in order to make diagnoses of perceived ailments. However, auscultation for animals such as cattle is used infrequently. There have been very few efforts made to gather data for auscultated bovine sounds for purposes of making conclusions as to the type of disease that may be occurring in bovine species.
Particularly in a feed yard where it is necessary for cattle to be maintained at an optimum state of health for the necessary weight gain to occur, it is critical that sick cattle be identified early for effective treatment and to contribute to biosecurity. The true state of health for cattle can be difficult to measure using traditional techniques such as observation of symptoms to include temperature, posture and visual signs (e.g. nasal discharge, depression, and abdominal fill.) Case definitions for Bovine Respiratory Disease have traditionally included an objective minimal rectal temperature and a subjective clinical score. Clinical trials indicate that objective lung scores provide stronger correlations than rectal temperatures to ultimate case fatality rates, retreatment rates, and treatment costs. Cattle are visually evaluated when they first arrive at the feed yard, and adrenalin associated with handling can often mask disease symptoms. Stethoscopic evaluation of bovine lung sounds can be used to evaluate the oxygen metabolism potential of cattle during various stages of arrival processing. However, because of the lack of current data in objectively categorizing bovine lung sounds, there is a need for developing an automated system and method that can assist a caregiver in assessing these lung sounds and making timely diagnoses.
Bovine respiratory disease is complex and is particularly difficult to treat and diagnose compared to respiratory diseases in humans. The thick musculature that surrounds the thorax of cattle, the heavy hide and possible layers of fat, and the breadth of the ribs complicates the use of a stethoscope to obtain sounds that can be analyzed for purposes of making a diagnosis.
Because of problems associated with effectively gathering auscultated sounds from cattle, and the general lack of knowledge as to how to analyze these sounds, the cattle industry has been slow in developing automated diagnostic processes that can effectively use auscultated data.
One patent reference that discusses the use of acoustics for detection of respiratory conditions is the U.S. Pat. No. 6,443,907. This reference specifically discloses diagnostic techniques to enable detection of respiratory conditions within a patient's body. Data gathered from auscultation is compared to reference acoustic characteristics and/or predetermined threshold values to determine if an abnormal respiratory condition is present within the patient. The diagnostic technique includes the processing of acoustic data by calculating energy ratios using energy values within high and low frequency bands, signal time delays, and/or dominant frequencies; the calculated values are then compared to predetermined reference thresholds to generate outputs indicative of the respiratory condition within the patient.
The U.S. Pat. No. 6,520,924 discloses an automatic diagnostic apparatus using a digital stethoscope. The diagnosis is determined based upon a comparison of recorded auscultated sounds versus standard data of auscultated sounds for cardiovascular, respiratory, and gastrointestinal diseases. Objective criteria are used to compare the collected auscultated sounds and the standard data to enable a medical practitioner to diagnose a particular disease.
Although auscultation has been well developed for human treatment, there is clearly a need for an automated process and method that can diagnose bovine respiratory diseases.